Salivary pH Changes and Biofilm Formation During Active Orthodontic Treatment with Clear Aligners and Fixed Appliances

Objective: To examine salivary pH changes and the plaque formation in two different orthodontic treatments clinically. Methods: The study sample included 40 patients, who were divided into two groups according to the type of orthodontic appliance: Group CA, (n=15) clear aligners; Group FT, (n=25) fixed appliances. Group FT received both metal (FT/SS) and elastic ligatures (FT/EM) for 2 weeks respectively to test the effect of ligature type also. Salivary pH values, plaque index, and plaque percentage were measured at T0 (after scaling and polishing) and T1 (after 2 weeks). pH was measured with a digital caliper (HI 2211 pH/ORP Meter) and plaque was identified by a discoloring agent (Tri Plaque ID Gel). The Paired t-test, Independent t-test, Anova test and Pearson Correlation tests were used in the statistical analysis. Results: There was significant decrease in salivary pH values after two weeks of metal ligature in FT/SS. Plaque index and plaque percentage parameters showed significant incremental changes between groups with the least increase in CA, followed by FT/SS and FT/EM respectively. Conclusion: Different types of orthodontic treatment and ligatures significantly effected salivary pH and the amount of plaque formation during orthodontic treatment. Aligners had the least effect on salivary pH and plaque formation while fixed treatment with elastic ligature affected the most. Therefore, aligner treatment may be more beneficial for patients with compromised oral hygiene.